Spectrometry is a technique used to assess the concentration or amount of a given material. The apparatus that performs such measurements is a spectrometer or spectrograph. Spectrometry is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from or absorbed by them. Spectrometry is also often used in remote sensing applications, such as explosive detection.
One example method of spectrometry is Raman spectroscopy. Raman spectroscopy uses the inelastic scattering of light to analyze vibrational and rotational modes of molecules. Because vibrational information is specific to the chemical bonds, atomic mass of the atoms in the bond and symmetry of molecules, Raman spectroscopy provides a “fingerprint” by which the molecule can be identified.
Another example method of spectrometry is Laser-induced breakdown spectrometry (LIBS). LIBS uses a high-power laser focused onto the surface of a sample to produce plasma. Light from the plasma is captured by spectrometers and the characteristic spectra of each element can be identified, allowing concentrations of elements in the sample to be measured.